Modular Construction System For Floating Structures Such As Boats

ABSTRACT

An assembly of mouldings that can be joined together and used as boats or other floating structures. The mouldings are advantageously of rotational moulded plastics material and can be of identical shape. Each of the mouldings has an outer face incorporating at least two zones that are advantageously flat and disposed at an angle one to the other so that one moulding can be joined to another face-to-face in different configurations. In one of such configurations, the first zone of one of the mouldings is in face-to-face relationship with one of the zones of another of the mouldings. In another embodiment the second zone of the one moulding is in face-to-face relationship with one of the zones of the other moulding. The mouldings have outer profiles that are substantially similar. The profiles are advantageously hexagonal. Some mouldings may be joined together end-to-end at end faces that are in face-to-face relationship.

FIELD OF THE INVENTION

This invention relates to a modular construction system for floatingstructures. The invention has been arrived at in the course ofdeveloping a system for boat construction using components made ofsynthetic plastics material formed by the rotational moulding process.However, the application of the invention is not limited to boats. Theinvention has application to floating platforms, floating storagevessels and the like.

BACKGROUND OF THE INVENTION AND PRIOR ART

Small boats such as kayaks, surf boards, runabouts and similar pleasurecraft comprising one piece hull-and-deck units for have been constructedof rotationally moulded plastics for some time. In a rotational mouldingprocess, medium density polyethylene or other suitable plastics materialin powder form is introduced into, a female mould having the inverseshape of an article to be moulded. The mould is then rotated while beingheated; typically being located in an oven for this purpose. Initiallythe powder is fluent and flows over the interior surface of the mould.When the mould surface reaches the correct temperature the particles ofpowder at the surface begin to melt and adhere to, the surface. Asheating continues, more of the particles melt, adhering to each otherand eventually forming a layer of uniform thickness on the surface ofthe mould. This layer solidifies to form the hollow shell-like mouldingwhen the mould is allowed to cool.

Rotational moulding techniques are well understood and need not bedescribed in further detail herein. It is believed that polyethylene isused for the moulding of most of such known craft although otherplastics materials may be suitable. The advantages of the use ofpolyethylene and other such materials for moulding boats and otherarticles are well known. Such boats are generally perceived, probablywith justification, as being inexpensive and tough. Moreover, thedensity of polyethylene and the other plastics materials used forrotational moulding is less than that of water so that small boats madeby this process have greater inherent buoyancy than boats that are madeof, for example, aluminum or GRP (glass-fibre reinforced plasticsresin).

From a marketing point of view, the appearance of objects made by knownrotational moulding techniques is often seen as a disadvantage for boatsbuilt for the leisure industry. However, for fishing boats and boatsused for some other commercial purposes, this may be less important. Thecompany with which the applicant is associated has for some timeproduced small fishing boats of up to 6 meters in length havingone-piece rotationally moulded hull-and-deck units. The size of suchunits is limited, in principle, by the size of available heating ovensused in the moulding process. From a business point of view, it would bevery risky at the present time for an enterprise to incur the expense ofa large size such oven in the absence of an established market for boatsof, say, 10 meters in length with rotationally moulded, one piecehull-and-deck units.

The present invention is an attempt to address this issue, at least tosome extent.

STATEMENTS OF INVENTION

According to the invention there is provided assembly of mouldings thatcan be joined together and used as a floating structure, the assemblycomprising a first moulding and a second moulding each of which isproduced by a rotational moulding process and has an outer faceincorporating a first zone and a second zone which zones are so shapedthat the first moulding can be joined to the second moulding in a firstdisposition in which the first zone of the first moulding is inface-to-face relationship with one of the zones of the second mouldingor in a second disposition in which the second zone of the firstmoulding is in face-to-face relationship with one of the zones of thesecond moulding.

Further according to the invention, the assembly of mouldings include athird moulding having an outer face incorporating a first zone and asecond zone which zones are so shaped that the third moulding can bejoined to the second moulding in a first disposition in which the firstzone of the third moulding is in face-to-face relationship with one ofthe zones of the second moulding or in a second disposition in which thesecond zone of the third moulding is in face-to-face relationship withone of the zones of the second moulding.

According to one aspect of the invention, the first zone and the secondzone of each moulding comprise each a flat portion of the outer face ofthe moulding, the flat portions being disposed at an angle one to theother.

According to another aspect of the invention, the mouldings have outerprofiles that are substantially similar one to the other. The advantageof this provision is that it is likely to reduce the cost of producing aboat or other floating structure that incorporates the assembly ofmouldings. Such mouldings can, for example, be produced from a singlemould, and the cost of two moulds is avoided. Clearly, mouldings thatare produced from a single mould will have substantially identicalprofiles when they are taken out of the mould. Equally clearly, in anystructure, the outer profile of a moulding may be modified after it istaken out of the mould. For example, in the case of a boat, holes may becut in a moulding for the purpose of providing hatches, portholes andthe like. For the purposes of this specification and the claims, thealteration of the outer profile of a moulding by the provision of suchis not considered to be substantial.

Similar considerations apply to other minor modifications to mouldings.

Advantageously, according to the invention, the three mouldings may havesubstantially similar outer profiles of hexagonal shape. A hexagonalprofile will thus be made up of six straight portions with the adjacentportions being disposed at equal angles one to the other.

The provision of similar mouldings with hexagonal outer profiles leadsto the possibility that a number of such mouldings can be joinedtogether in a wide variety of configurations in each of which one of theflat-faced portions of one moulding is disposed face-to-face with one ofthe flat-faced portions another moulding. Mouldings produced from asingle mould, and therefore incorporating substantially similarflat-faced portions can therefore be used to produce a variety of boatsand other floating structures.

In another aspect of the invention, at least one moulding has an endface that is disposed in face-to-face relationship with an end face of afourth moulding to which said at least one moulding is joined. Joiningthe mouldings together end to end enables boats and other floatingstructures of increased to length to be produced from rotationallymoulded mouldings whose length is limited by the size of the equipmentthat is available for the moulding process.

Advantageously, according to the invention, the mouldings are of mouldedplastics material.

The scope of the invention extends to a hull-and-deck structurecomprised of an assembly of the mouldings.

DESCRIPTION OF EMBODIMENTS ILLUSTRATED IN THE DRAWINGS

Examples of apparatus that embody the invention are described below withreference to the accompanying drawings in which:

FIG. 1 is a side elevation of the hull-and-deck assembly of a twinhulled boat, or catamaran, incorporating a number of modular mouldings;

FIG. 2 is a side elevation of a pair of the mouldings shown in FIG. 1 intheir working disposition;

FIG. 3 is a side elevation, on Arrow A in FIG. 4, of three of themouldings shown in FIG. 1, also in their working disposition;

FIG. 4 is a plan view of the hull-and-deck assembly shown in FIG. 1;

FIG. 5 is a plan view of the pair of mouldings shown in FIG. 2;

FIG. 6 is a plan view of the mouldings shown in FIG. 3;

FIG. 7 is an isometric view of the two mouldings shown in FIG. 2, withone moulding, only part of which is illustrated, detached from theother;

FIG. 8 is an isometric view, similar to FIG. 7, of two of the mouldingsshown in FIG. 3;

FIG. 9 is an isometric view of two of the mouldings shown in FIG. 3;

FIG. 10 is a rear end elevation (on Arrow B) of the hull-and-deckassembly shown in FIG. 1;

FIGS. 11-13 are enlarged details of possible joints between twomouldings;

FIG. 14 is an end elevation of a hull-and-deck assembly for atrimaran-type boat;

FIGS. 15-16 are views of assemblies of mouldings that can be used asfloating platforms;

FIG. 17 is a view of an assembly of other mouldings that can be used asa floating structure; and

FIG. 18 is a fragmentary view of an optional modification to a moulding.

For the sake of avoiding repetition, in this specification the use ofthe phrase “in the present example” or words to the same effect isintended to indicate that what is being described is by way ofillustrative example. In such cases it should be clear from the contextthat what is being described can be changed and that there is nointention that the scope of the invention be limited thereto. The natureof many of such changes should also be clear to the instructed reader.On the other hand, there is no intention that, in the absence of aphrase of the same kind, the scope of the invention is to be limited toany matter described unless this appears from the context.

It will be clear to the instructed reader that the drawings show,essentially in schematic form, the disposition of the mouldings whenthey have been assembled together to form examples of floatingstructures and, more particularly, of boats. The mouldings of the typedescribed herein may be of medium density, polyethylene but they couldbe of any other suitable material suitable for being used in rotationalmoulding techniques. Such materials include PVC, cross-linkedpolyethylene and even concrete. As has already been stated, rotationalmoulding techniques are well understood. No claim is made that the useof a rotational moulding process, or of any materials used in theprocess, is in itself inventive for producing boats.

Equally well understood are the components such as the engines, internaland external fittings and furniture, ground tackle, navigationequipment, fishing gear etc., and the manner of installation of all ofthese, that are required to turn a hull-and-deck assembly into a workingboat. Again it is not considered necessary to describe these mattersherein in detail as they do not form part of the invention.

Referring now to the drawings, there is shown a hull-and-deck assembly10 that can be fitted out to form a twin-hulled boat or catamaran. Toavoid repetition, it will be convenient to refer to this particular boatas boat B even though the finished boat is not shown in the drawings.

In FIGS. 1-6, 10 the mouldings are shown slightly separated from eachother in some places. This is for clarity of illustration. In reality,the mouldings are structurally joined to each other face to face inthese places.

In the present example, the assembly is made up of eight mouldings, eachof which is of polyethylene material and is produced by a rotationalmoulding process using suitable moulds. It is an inherent feature of anyarticle produced by a rotational moulding process that, when it emergesfrom the mould, it comprises in essence a hollow shell that is fullyclosed except for one or more small vent holes necessary for allowinggases evolved in the process to escape. One advantage arising from theuse of such mouldings for building boats is that they are inherentlywatertight and thus capable of floating. Holes, some examples of whichwill be described, may be cut in all of the mouldings in the course ofconstruction of the boat B. Some of these holes are quite large and,unless they are closed by watertight doors or the like (a technique wellknown in ship- and boat-building techniques), will reduce thefloatability of the individual mouldings. Nevertheless, as should beobvious, the fact that the mouldings are initially enclosed facilitatesthe design and construction of a boat that is less prone to sinking inrough weather or when holed. The floatability is aided by the fact thatthe density of polyethylene is lower than that of water. The materialitself is thus buoyant.

As already noted, the mouldings that are produced from any one mouldwill be mutually identical, at least in the state that they are in whenthey emerge from the mould. Thus, in the case of the assembly 10, thereis one group M1 comprising three mutually identical mouldings producedfrom one mould; a second group M2 comprising two mutually identicalmouldings produced from a second mould; another group M3 comprising twomutually identical mouldings produced from a third mould; and a singlefurther moulding produced from a fourth mould M4. All of these mouldingswill be described. Since the mouldings in each group of the groups M1-M3are identical, for most purposes herein only one of the mouldings ineach group need be described.

An important feature of the six mouldings in the groups M1, M2 and M4 istheir mutually similar athwartships outer profile which, in the presentinstance, is hexagonal although a variety of other shapes, some examplesof which are illustrated and/or described herein, could be used. Thehexagonal shape can be seen in FIGS. 10, 14-16. All such profiles are ofconstant size over the entire length the mouldings. Thus each of themouldings in the groups M1-M3 comprises a longitudinally extending,cylindrical side wall 12 of hexagonal cross section having six flat,rectangular segments 14A, 14B, 14C, 14D, 14E, 14F that are disposed at120° one to the other. The segments are of equal size and extend in thefore-and-aft direction from one end of the moulding to the other end.Each segment has a flat outer face.

Each moulding, 16, 18, 20 in the first group M1 comprises a flat frontwall 22 spanning the front end of the moulding and a flat back wall 24spanning the back end of the moulding. The walls 22, 24 areperpendicular to the outer faces of the segments 14A-F.

The moulding 16 is positioned between the mouldings 18, 20. In thisstate, the entire outer face of segment 14A of moulding 16 isface-to-face with the entire outer face of segment 14D moulding 18.Similarly the entire outer face of segment 14C of moulding 16 isface-to-face with the entire outer face of segment 14F of moulding 20.The mouldings 16, 18 are joined together by suitable fastening meanswhich, in the present case, may include bolts 26 (see FIG. 12) that arepositioned at intervals around the peripheries of the interfacingsegments 14C, 14F and clamp them together. It is of course necessary toprovide holes 28 in the wall 12 at the interfacing segments toaccommodate the bolts. The mouldings 16, 20 are joined together in thesame manner with the interfacing segments 14A, 14D clamped together.

It will often be necessary to cut registering holes 30, 32 in theinterfacing segments of the walls of the mouldings 16, 18 to provide adoorway or other manhole for human access between the two mouldings. Asnoted, the manhole can be closed by a watertight door when the boat B isfitted out. Further bolts or other fastenings may be provided around theholes 30, 32 for clamping the interfacing segments together. Similarholes can be provided in the interfacing segments of the mouldings 16,20.

The mouldings 36, 38 in the second group M2 are positioned in front of,and in alignment with the respective mouldings 18, 20. Each moulding 36,38 also comprises a longitudinally extending, cylindrical side wall 12′which, at the rear end of the moulding, is of hexagonal cross sectionand embodies six segments 14A′, 14B′, 14C′, 14D′, 14E′, 14F′,equiangularly disposed one to the other. The segments extend forwardlyfrom the rear ends of the mouldings 36, 38 in the fore-and-aftdirection. Flat rear walls 24′, integrally moulded with the walls 12,span the rear ends of the mouldings 36, 38. At the rear ends, the walls24′ are perpendicular to the wall 12′ and more particularly to the outerfaces of the segments 14A′-F′. Thus, where the mouldings 36, 38 meet therespective mouldings 18, 20, the outer faces of the segments 14A′-F′ arecoplanar with the outer faces of the respective segments 14A-F. However,forward of the rear ends of the mouldings, the profiles of the segments14A′-F′ differ from those of the respective segments 14A-F14 and alsodiffer from each other as will be explained.

The single moulding 42 produced from the mould M4 is positioned in frontof, and in alignment with the moulding 16. The moulding 42 alsocomprises a longitudinally extending, cylindrical side wall 12″ which,at its rear end, is of hexagonal cross section and embodies six segments14A″, 14B″, 14C″, 14D″′, 14E″, 14F″, equiangularly disposed one to theother. The segments extend forwardly from the rear end of the moulding42 in the fore-and-aft direction. An integrally moulded flat rear wall24″ spans the rear end of the moulding 42. At this end, the wall 24″ isperpendicular to the wall 12″ and more particularly to the outer facesof the segments 14A″-F″. Thus, where the moulding 42 meets the moulding16, the outer faces of the segments 14A″-F″ are coplanar with the outerfaces of the respective segments 14A-F of moulding 16. However, forwardof the rear end of the moulding 42, the profile of the segments 14A″-F″differ from those of the respective segments 14A-F14 of moulding 16 andalso differ from each other as will be explained.

When the mouldings 36, 38, 42 are positioned as just described, due totheir size and shape, the outer face of the segment 14F′ (moulding 36)has a flat portion that meets a flat portion of the outer face of thesegment l4C″ (moulding 42) face-to-face. Similarly the outer face of thesegment 14D′ (moulding 38) has a flat portion that meets a flat portionof the outer face of the segment 14A″ (moulding 42) face-to-face.

The mouldings 36, 38, 42 are joined to the respective mouldings 18, 20,16 by suitable fastenings such a bolts 44 passing through holes 48 thatare formed at intervals around the peripheries of the interfacing walls24′, 24″, 22 and clamp them together. Similarly the mouldings 36, 38, 42are joined together by bolts 26 around the peripheries of the areaswhere the flat portions of the outer faces of the respective segmentsinterface.

Again it will often be necessary to cut registering holes (such as 30′,30″) in the walls of the respective mouldings where they interface. Asbefore, bolts or other fastenings may be mounted provided around theseregistering holes for clamping the walls together.

In the present case, the vertical overall height of each of themouldings in groups M1-M3 is 2.05 meters. Due to the nature of therotational moulding process, each of these mouldings has a uniform wallthickness of about 3 cm all round. Allowing for the wall thickness, theinternal vertical height of each moulding is thus 1.99 meters so thatthere is likely to be plenty of head room in each of the six mouldings,even allowing for the installation of a floor located above the bottomof the moulding when the boat B is fitted out. Any other suitable heightcould be chosen.

As noted, the assembly 10 is intended to be fitted out as a catamarantype boat B. In this configuration, the assemblies comprising thealigned moulding pairs 36, 18 and 38, 20 constitute the two hulls of theboat with the mouldings 36, 38 located at the forward ends of the hulls.For this reason, the segments 14A′, 14C′ of each of these mouldingstaper inwardly towards their front ends as shown at 50. Similarly thehorizontal segments 14B′ located at the bottoms of the moulding 36, 38taper upwardly towards their front ends as shown at 52. In both casesthis is to promote a clean passage of the hulls through the water.

The hull assemblies are joined structurally together, and separated by,the assembly comprising the aligned moulding pair 42, 16 which is raisedabove the water. This assembly can be fitted out as a saloon with asteering- and control station at its forward end. For this reason, themoulding 42 is formed with a steeply sloping portion 54 that is disposedathwartships and extends between the segments 14D″ and 14F″. A hole 56can be cut in this portion for accommodating a windscreen.

Even though the saloon assembly is raised above the water, good boatdesign may dictate that the horizontal segment 14B″ located at thebottom of the moulding 42 should taper upwardly towards its front end asshown at 58. Again this is to promote a clean entry of the front end ofboat B through any water that reaches the level of the saloon assemblyas often happens at sea.

The horizontal upper segments 14E, 14E′ and 14′″conveniently constitutesubstantial deck areas for the boat B. Access to these deck areas can begained through, for example, doorways or manholes formed by holes 60 cutin the segments 14D, 14F of moulding 16 and/or in the segments 14D″,14F″ of moulding 42. As before, these manholes can be sealed bywatertight doors.

Further holes 62 can be cut in the segments 14D, 14D″, 14F, 14F″ toaccommodate portholes of known type.

There are two mouldings 64, 66 in group M3, attached to the rear ends ofthe respective mouldings 18, 20. Although the mouldings 64, 66 aremutually identical, they differ somewhat from the mouldings in groupsM1-M3 in that they are not of hexagonal cross section. Instead, each isof the shape of a half-hexagon of the same size as that of the mouldingsin groups M1-M3. Thus moulding 64 comprises a longitudinally extendingsidewall 12′″ incorporating three segments 14A′″, 14B′″ and 14C′″ of thesame size as, and coplanar with, the respective segments 14A, 14B and14C. Further, moulding 64 comprises a front wall 70 and a rear wall 72each of which is perpendicular to the sidewall 68. Finally, moulding 64comprises an upper wall 76 that extends between the upper ends of endwalls 70, 72 and also between the upper ends of segments 14A′″ and14C′″. Moulding 64 (and similarly moulding 66) thus comprises a unitaryenclosed shell when it is taken out of the mould M3. The front wall 70is disposed face-to-face with the lower half of the rear wall 24 ofmoulding 18. As before, moulding 64 (and also moulding 66) is joined tomoulding 18 by suitable fastenings such as bolts 44 that pass throughholes positioned at intervals around the peripheries of the interfacingparts of walls 70, 24 and clamp them together. A hole for creating amanhole similar to those provided elsewhere, may be cut in the wall 70and further holes for accommodating fastenings may be drilled around themanhole for clamping the interfacing wall parts together. A hole 78 canbe cut into the upper walls to constitute a hatch for giving access tothe interior of moulding 64. The hatch can be closed by a watertighthatch cover of known type.

Each moulding 64, 66 can conveniently be designed to accommodate, inknown manner, an engine and propeller shaft for boat B. Each propellershaft would pass through a hole cut in the lower segment 14B′″ of themouldings. The hole would be closed by known means fixed to the segment14B′″ for housing a bearing and gland for the propeller shaft.

FIGS. 1-6 are drawn to the same scale and from this it can be seen thatthe overall length of the particular assembly 10 shown in FIGS. 1-6 is13 meters, and the beam is 6 meters. Clearly, two or more sets of threeM1 mouldings joined together as described above could be mountedend-to-end to increase the length of the assembly 10.

Because the outer faces of various wall segments are coplanar asdescribed, such coplanar faces present a continuous smooth surfaceextending from the front of the boat to the back. As is well know, thisis important for smoothing the passage of the hulls through the water.

An advantage of the invention is that the same mouldings can be used forboats and other floating structures of various shapes. For example, themouldings heretofore described and illustrated in the drawings could beused to construct a hull-and-deck assembly 100 for a trimaran-type boathaving the cross-sectional shape as shown in FIG. 14 which is anentirely schematic end view of the rear of the assembly 100. Here agroup of six of the mouldings from mould M1 are joined together as asub-assembly 102 forming part of a boat with three hulls incorporatingM1 mouldings 104, 106, 108. Because of the size of this boat, it maycomprise two or more of such sub-assemblies 102 disposed one in front ofthe other. As in the case of boat B, mouldings from mould M2 may bemounted at the front of each of the mouldings 104-108 and a mouldingfrom mould M4 may be mounted at the front of the central upper moulding110. A moulding from mould M3 may also be mounted at the back end ofeach of the mouldings 104, 106,108.

FIG. 15 is a similarly schematic view of an assembly 120 that is oneexample of a structure that could be used as a floating platform. In thepresent case, the assembly comprises three floating shells in the formof mouldings 122, 124, 126 from mould M1. The shells are spaced apart bytwo watertight shells in the form of two mouldings 128, 130 from mouldM3 which, in use, are lifted above the water by the mouldings 122-126.

In one variation, the assembly 120 could be provided with additionalmouldings 128′, 130′ from mould M3, located below the respectivemouldings 128, 130.

In another variation, the assembly 120 could be inverted to act as onevariation of the floating platform. In this version, all of the modulesare located at water level and there would be two channel-like spaces132 between the mouldings 122, 124, 126 which might make the platformparticularly useful for some purposes

FIG. 16 shows how a series of modules from moulds M1, M3 could be joinedtogether to form an assembly 140 for a floating platform of anyreasonable size and having a continuously flat upper surface or deck. Asshould be clear from the foregoing description, a series of theassemblies could be joined together honeycomb fashion to increase thesize of the platform. In the assembly 140, the longitudinal axes of themouldings are vertically disposed.

The useful shapes of the modules are not necessarily limited to thoseshown in the Figures discussed to this point. FIG. 17 shows modules 150from a single mould but having a non-symmetrical shape. Each module hastwo wall segments 152, 154 either of which can be brought face-to-facewith a corresponding wall segment of the other module when the modulesare joined together in the alternative configurations shown.

Those skilled in the art will be aware that it is necessary to provideelements such as stiffening ribs, gussets and the like at various placesin the mouldings to give them adequate strength and also, for example,to prevent distortion of the plastics material as it cools in the mould.As is well known, these elements can be formed during the mouldingprocess as integral parts of the moulding. By way of example, FIG. 18shows a wall segment (segment 14B in this instance) with integrallymoulded, longitudinally extending ribs 99. These ribs serve to stiffenthe wall segment and also to promote clean flow of water along the outerface of the segment when the moulding is incorporated in a boat hull.

The modules, shown FIGS. 14-17 can be joined together in substantiallythe same manner as heretofore described with reference to the assembly10. Those skilled in the art will be aware of alternative means ofjoining together any of the mouldings shown herein. Furthermore, theother features heretofore described that are incorporated in theassembly 10 may be replicated in each of the assemblies shown in FIGS.14-17 and need not be repeated here.

One alternative means for joining the mouldings together is shown inFIG. 13 and comprises a plate 90, also of plastics material, thatoverlaps a joint 92 between two mouldings. The walls of the mouldingsmay be provided with recesses 94 formed during the moulding process toaccommodate the plate 90 which can be through bolted to the walls bybolts 96 or other fastenings.

Alternatively or in addition, two mouldings can be welded together atthe joints therebetween, as shown at 98 in FIGS. 11 and 12. It may bedifficult to achieve welded joints between two rotationally mouldedcomponents that, by themselves, are strong enough for practicalpurposes. However, such welded joints may be useful to make the jointswatertight and also to give the joints a finished appearance.

The foregoing examples demonstrate that the mouldings described can bejoined together in two or more different configurations to make upassemblies that can be used as boats or other floating structures. Themouldings are of moulded plastics material. Each of the mouldings has anouter face incorporating at least two zones that are so shaped that onemoulding can be joined to another in at least two dispositions. In oneof such dispositions, the first zone of one of the mouldings is inface-to-face relationship with one of the zones of another of themouldings. In another of such dispositions, the second zone of the onemoulding is in face-to-face relationship with one of the zones of theother moulding.

Moreover, such assemblies can be made up of three or more of themouldings with outer faces shaped so that the mouldings can be similarlyjoined together.

It is not intended that recognized mechanical equivalents of and/ormodifications of and/or improvements to any matter described and/orillustrated herein should be excluded from the scope of a patent grantedin pursuance of any application of which this specification forms a partor which claims the priority thereof or that the scope of any suchpatent should be limited by such matter further than is necessary todistinguish the invention claimed in such patent from the prior art.

1. An assembly of mouldings that can be joined together and used as afloating structure, the assembly comprising a first moulding and asecond moulding each of which is produced by a rotational mouldingprocess and has an outer face incorporating a first zone and a secondzone which zones are so shaped that the first moulding can be joined tothe second moulding in a first disposition in which the first zone ofthe first moulding is in face-to-face relationship with one of the zonesof the second moulding or in a second disposition in which the secondzone of the first moulding is in face-to-face relationship with one ofthe zones of the second moulding.
 2. An assembly of mouldings accordingto claim 1, in which the mouldings include a third moulding having anouter face incorporating a first zone and a second zone which zones areso shaped that the third moulding can be joined to the second mouldingin a first disposition in which the first zone of the third moulding isin face-to-face relationship with one of the zones of the secondmoulding or in a second disposition in which the second zone of thethird moulding is in face-to-face relationship with one of the zones ofthe second moulding.
 3. An assembly of mouldings according to claim 1,in which the first zone and the second zone of each moulding compriseeach a flat portion of the outer face of the moulding, the flat portionsbeing disposed at an angle one to the other.
 4. An assembly of mouldingsaccording to claim 1, in which the mouldings have outer profiles thatare substantially similar one to the other.
 5. An assembly of mouldingsaccording to claim 4, in which the mouldings have substantially similarouter profiles that are of hexagonal shape.
 6. An assembly of mouldingsaccording to claim 1, in which at least one moulding has an end facethat is disposed in face-to-face relationship with an end face of afourth moulding to which said at least one moulding is joined.
 7. Anassembly of mouldings according to claim 1, in which the mouldings areof moulded plastics material.
 8. A hull-and-deck structure for a boatcomprising an assembly of mouldings according to claim 1.